The main function of packaging is to wrap components in a package, this not only plays a role in mounting, fixing, sealing, protecting a chip and enhancing the electrical and thermal properties, but also connects the contacts on the chip to the pins of the package through wires, and these pins are connected with other devices through wires disposed on a circuit board so as to realize the connections between an internal chip and an external circuit. The chip must be isolated from the outside in order to prevent the chip circuit from being corroded by impurities in the air and water vapor to cause reduction of the electrical performance. In addition, the packaged chip is also more convenient to install and transport. The packaging technology has a direct impact on the performance of the chip itself, as well as the design and the manufacture of the circuit board connected, so the packaging is crucial.
Due to the ever-increasing requirements of whole electronic equipment and systems for high-density assembly such as miniaturization, light weight and thinning in the fields such as aviation, aerospace and computers, electronic assembly will develop towards the three-dimensional assembly on the basis of the two-dimensional assembly for a limited area and gradually develop to the system-level packaging.
However, the traditional packaging technology has high complexity process and low precision, and requires to design and manufacture different packages for different chips, which involves the production of the mold, the complex entire manufacturing process, time-consuming and costly. Thereby it seriously restricts the progress of research and development.